1) Pachycephalosaur 
Pachycephalosaurus (s; meaning `thick headed lizard,` from Greek pachys-/παχυς- `thick`, kephale/κεφαλη `head` and sauros/σαυρος `lizard`) is a genus of pachycephalosaurid dinosaurs. The type species, P. wyomingensis, is the only known species. It lived during the Late Cretaceous Period (Maastrichtian stage) of what is now...
genus of large and unusual dinosaurs found as fossils in deposits of North America dating to the Late Cretaceous Epoch (97.5 to 66.4 million years ... [1 related articles]
Pachycephalosaurus was a dinosaur of the Cretaceous period. Pachycephalosaurus was about eight metres long, walked on its hind legs and was furnished with a thick top to the skull.
Pachycephalosaurus, Pachycephalosaur A “thick-headed lizard” from Late Cretaceous Montana. Named by paleontologist Barnum Brown (1873-1963) and Schlaikjer in 1943.